1. Field of the Invention
The present invention relates to an electronic data management technique and, more particularly, to an electronic data processing technique having link information to external electronic data.
2. Description of the Related Art
Recent electronization of documents are promoting introduction of document data management systems to offices to manage electronic data. In general, the document data management system comprehensively manages document data stored in various devices. The user can execute operations such as search, browsing, and download for stored document data.
The document data management system can create a file (link data) containing link information to access another file (actual file), similar to a file system for an operating system (OS). That is, link data holds not actual data but only referring information (path information) to another file. The use of link data can prevent the existence of many electronic data with the same contents. The disk capacity and the network traffic in electronic data operation can be reduced.
However, the following problem occurs when link data referring to an actual file in a given client PC (PC1) is copied or moved to a shared disk on a network or is attached to mail and sent. More specifically, when another client PC (PC2) different from the PC1 uses the link data, it cannot access an actual file or accesses another erroneous actual file.
To solve this problem, for example, Japanese Patent Laid-Open No. 2006-301746 discloses a technique of checking whether there is information at a link destination, and if there is no such information, deleting the link information. Japanese Patent Laid-Open Nos. 2003-223404 and 2007-011730 disclose techniques of, when attaching link data to e-mail and sending it, switching which of link data and an actual file at the referring destination is to be attached to e-mail. The determination is made especially based on the connection status of the transmission destination and the presence/absence of a right to access the referring destination of link data.
According to the conventional techniques, however, to properly use link data and an actual file, it is necessary to mange user information in a server or set in advance a condition for the proper use. Also, the conventional techniques do not consider a case in which a so-called structured file containing one or more files includes a link information file mentioned above. When a structured file is exchanged between different devices, it sometimes becomes impossible to refer to a link destination.